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Biomedical subjects

N N Firsov

Publications and source records attributed to N N Firsov.

At least 19 recordsLinked to original sources
PubMed2004

The influence of cryoglobulins on the temperature-dependent erythrocyte aggregation in vitro by backscattering nephelometry.

Nephelometry technique was used to register the alterations of the scattering signal from a whole blood sample due to erythrocyte aggregates in stasis and under controlled shear stress. The measured parameters were: the characteristic times of linear and three-dimensional aggregates formation, and the strength of aggregates of different types. These parameters depend on the sample temperature in the range of 2/50 degrees C. Temporal parameters of the aggregation process strongly increase (by 3 times) at temperature 45 degrees C. For samples of normal blood the aggregates strength parameters do not significantly depend on the sample temperature, whereas for blood samples from patients with cryoglobulinemia high increase of the strength of both three-dimensional and linear aggregates and decrease of time of linear aggregates formation at low temperature of the sample (4 degrees C) was observed. The difference of these parameters of the pathological blood from that of the normal at room temperature was quite opposite. Possible reasons of such behavior of aggregation state of blood and explanation of the observed effects are suggested.

Cryoglobulinemia↗
PubMed2002

[Alterations of rheological properties of blood in systemic sclerodermia].

AIM: To study hemorheological status in systemic sclerosis (SS) patients. MATERIAL AND METHODS: Macro- and microrheology of blood were investigated in 70 SS patients. The rate of spontaneous aggregation of red blood cells [T1(s)], durability of the largest units [Ia2.5(%)], general hydrodynamic durability of units [beta(s-1)], limit of fluidity [tau 0 (mPa)], Casson viscosity K (mPa/s) were determined. RESULTS: The total severity of hemorheological disturbances was 1.90 +/- 0.07 with T1 = 4.98 +/- 1.52s, beta = 62.76 +/- 19.32s, Ia 2.5 = -0.78 +/- 12.83%, tau 0 = 7.00 +/- 0.45 mPa. The Casson viscosity did not differ from normal levels. Plasma viscosity was 1.71 +/- 0.18 rel units, viscosity of sera 1.55 +/- 0.14 rel.units. The severity of hemorheological disturbances did not differ in cute and chronic courses but the parameter beta (72.0 +/- 4.5) was significantly higher (p < 0.05) in the acute course. The severity of hemorheological disturbances was highest in SS patients with cardiac disease (p < 0.05) and in 10 year SS duration. CONCLUSION: The course of SS is complicated by progressive hyperaggregation syndrome promoting development of visceral pathology. Active correction of hemorheology is pathogenetically validated in SS.

Adolescent↗
PubMed2000

[Hyperaggregation syndrome in patients with osteolytic psoriatic arthritis].

AIM: To study blood rheology in patients with psoriatic arthritis (PA) having local or advanced osteolysis. MATERIALS AND METHODS: The trial included 16 patients with significant PA and clinical and x-ray symptoms of joint surface osteolysis. Kinetics of red cell aggregation and disaggregation was studied in specially designed erythroagregometer. RESULTS: The assessment of red cell aggregation indicated the presence of hyperaggregation syndrome in the majority of PA patients with associated osteolysis. CONCLUSION: Hyperaggregation may contribute to bone destruction. Its onset can be reviewed as a risk factor for serious destructive changes in the joints.

Adolescent↗
PubMed1998

Clinical application of the measurement of spontaneous erythrocyte aggregation and disaggregation. A pilot study.

Aggregation and disaggregation kinetics of erythrocytes in samples of whole blood were studied using a backscattering nephelometry technique. Blood was drawn from normal subjects and from patients suffering from different diseases: chronic glomerulonephritis, systemic lupus erythematosus, hereditary hypercholesterolemia, pulmonary hypertension, intestinal tumors preoperatively (age > 60 years), psoriasis, psoriatic arthritis, ischemia and ischemia with diabetes. Blood samples of healthy donors were used as controls. The backscattering signal in the erythroaggregometer was processed according to algorithms yielding quantitative data on the full amplitude of aggregation, characteristic times of spontaneous aggregation, average hydrodynamic strength of all aggregates and, whenever possible, additionally, strength of the largest aggregates. The obtained results confirm that the complexity of erythrocyte aggregation kinetics requires multiparametric description which, when applied to clinical material, enables the differentiation of aggregation characteristics between diseases.

Biomarkers↗
PubMed1991

[Microcirculatory disorders in patients with psoriatic arthritis].

As many as 39 patients with psoriatic arthritis were examined for hemorheology. Of these, 20 were examined at a time for the status of the microcirculatory bed in the skin and skeletal muscle by 133Xe clearance from the interstitial depot and by laser-Doppler flowmetry at the areas of the clinically intact skin. In 10 patients, the plasma blood viscosity was measured. All the test subjects manifested the clinical signs of damage to the vessels of the microcirculatory bed, namely capillaritis of the palmar surface of the hands and/or of the plantar surface of the feet, sensitivity to cold, numbness of the finger tips. A detailed analysis of the individual aggregation characteristics allowed two groups of patients to be revealed: with a decrease and enhancement of aggregation at a shift rate of 2.5 s-1. It should be noted that patients with severe hemorheological disorders showed both changes on the part of the microcirculatory bed (clinical and quantitative) and a rise of the blood plasma viscosity and hematocrit fall. The data obtained indicate that the microcirculatory and related rheological disorders may be implicated in the pathogenesis of psoriatic arthritis.

Adolescent↗
PubMed1989

[Ultrasonic placentometry in pregnancy].

The authors developed mathematical formulas for the determination of the size of the placenta during the pregnancy based on the technique of ultrasonic scanning. Healthy pregnant females with 19-40 weeks of gestation underwent ultrasonic placentometry. Reference placental volumes were defined. The authors demonstrated an increment in the placental volume and its growth rate with evolving pregnancy.

Adolescent↗
PubMed1989

Rheological properties of the blood in psoriasis patients during PUVA-therapy.

Rheological properties of the blood in 50 psoriasis patients were studied during PUVA-therapy. The mean rheological indices in half of the patients were above normal before treatment. During the PUVA-therapy the mean indices in this group of patients were near to normal. Bimodal distributions of the obtained indices were connected neither with each other, nor with the form and severity of the disease. Lack of statistical correlation links between quantitative indices of systems defining an aggregate state of the blood leads one to believe that changes in rheological properties of the blood in psoriasis patients before treatment can be connected with the immune status of the major disease. Further research in this field is needed.

Adult↗
PubMed1988

[Blood rheologic properties in patients with dilated cardiomyopathy].

Rheologic blood parameters--fluidity limit tau 0, viscosity n alpha 1, erythrocyte cohesion coefficient (A), hematocrit--were studied in 42 patients with dilated cardiomyopathy (DCM) and 30 patients with ischemic heart disease (IHD) and heart failure of stages I-III. Rheologic parameters tended to increase along with progression of heart failure while in IHD an opposite tendency was observed. Individual analysis in patients with DCM as well as those with IHD demonstrated, irrespectively of the stage of heart failure, both hyper- and hyporheological syndromes. Occurrence of thromboembolic complications was in both cases nearly the same (42.9% and 40%, correspondingly). The data obtained indicate at evident abnormality of rheologic blood parameters in patients with dilated cardiomyopathy progressing along with development of heart failure and suggest its possible role in intravascular thrombi formation.

Adolescent↗
PubMed1985

[Mechanisms regulating the macrorheologic properties of the blood].

Macro-rheological features of human blood (the limit of fluidity, seeming viscosity in low shift velocities), cohesion power among erythrocytes, and hematocrit in pregnancy (36-38 weeks), in neonatal period, in acute and chronic heart disease, and in dogs with experimental hemorrhagic shock, were studied. Reduction of the cohesion power among erythrocytes was shown to occur in increase of hematocrit value. If the cohesion power increases it is followed by physiological hemodilution. The organism tries to prevent the increase of the macro-rheological parameters up to the level entailing irreversible disorders of microcirculation.

Animals↗